Risk factors associated with true knots of the umbilical cord

Objective: To determine obstetrical risk factors and pregnancy outcome of f etuses with true knot of the umbilical cord. Methods: Study population incl uded 69,139 singleton deliveries occurring between the years 1990-1997. Dat a were retrieved from the database of the Soroka University Medical Center. Fetuses with malformations were excluded. Results: The incidence of true k nots was 1.2% (841/69,139). In a multivariate analysis the following factor s were found to be significantly associated with true knot of cord: grand m ultiparity, chronic hypertension, hydramnios, patients who under-one geneti c amniocentesis, male gender and cord problems (prolapse of cord and cord a round the neck). The incidence of fetal distress and meconium stained amnio tic fluid was significantly higher among patients with true knots of cord ( 7% versus 3.6%, P < 0.001 and 22% versus 16%, respectively, P < 0.0001). Mo reover, there was a four-fold higher rate of antepartum fetal death among t hose fetuses (1.9% versus 0.5%, P < 0.0001). In addition, fetuses with true knots of the umbilical cord were more often delivered by a cesarean sectio n (130/841 versus 711/68,298, P < 0.0001). The following obstetrical factor s were found to be significantly correlated to true knots of the umbilical cord in a multiple logistic regression model: gestational diabetes, hydramn ios, patients undergoing genetic amniocentesis, male fetuses. Conclusions: Patients with hydramnios, who underwent genetic amniocentesis and those car rying male fetuses are at an increased risk for having true knots of the um bilical cord. Thus, careful sonographic and Doppler examinations should be seriously performed in these patients for detection of the complication of the umbilical cord. (C) 2001 Elsevier Science Ireland Ltd. All rights reser ved.